A pertinent device of the above-mentioned type is described and illustrated in German OS 2 113 775. This known sealing device is characterized by an air bellows being fitted to both the upper and the lower edges of the fuselage gap. Each air bellows is constructed in one piece. The two air bellows are associated with one another such that they contact one another or overlap partly when the movable wing is swung out from the fuselage gap. The air bellows have partition walls which are arranged in lateral direction and which extend parallel to one another to give the bellows, in the inflated condition, the necessary stability of shape.
The air bellows consist of a flexible, resilient material in order to satisfactorily function as a sealing device. Basically one uses herefore suitable plastics or rubber in foil shape, which can be reinforced by a resilient fiber material, and which are usually fixed to rigid base plates and/or are connected directly with the aircraft structure.
The inventive device is a seal for seaing off a fuselage gap in aircraft, which gap is adapted to receive a wing which can be swung partly into the fuselage gap. The fuselage gap is to be sealed off in each position of the wings by means of inflatable, flexible air bellows which have their outer surfaces shaped as to line up with the overall shape of the aircraft fuselage when in the inflated condition. The air bellows are arranged in pairs with respect to one another, so that they contact one another when the wing is in the swung-out configuration. One air bellows is connected on both the upper and lower edges of the fuselage gap. Each one contains partition walls on the inside thereof oriented in lateral direction and, parallel to one another with openings therethrough.
Due to the relatively complicated structure of the air bellows, it is difficult to simultaneously satisfy all requirements demanded from them during manufacture and installation. They are to have a low weight and be sufficiently stable, robust and also flexible.
To attain this purpose, the air bellows shall be manufactured with a triangular-shaped cross section and the partition walls fixedly connected to the bellows along two edges, while the third edge is connected to the associated bellows wall through a form-closed mechanism. The form-closed mechanism consists preferably of one hinge.
This structure has decisive manufacturing and technological advantages. During manufacture the partition walls can be connected on two edges to the two adjacent sheath wall surfaces easily since access is possible from the third, open sidewall. The connection at these edges may be formed by bonding, curing, sewing or welding. The third wall of the air bellows is connected to the free edges of the partition walls, for example, through hinges, after which the overlapping peripheral edges are, as a last operation, sealed off e.g. by bonding.
Important advantages are derived from the invention:
1. Considerable weight savings compared with air bellows comprising the base plate concept because a third elastic wall is usually much lighter than rigid plates and the hinges are considerably smaller and lighter than the clamping strips in the case of base plates. The load absorption in the hinge construction is much more favorable than in a clamping connection.
2. Easier sealing capability on the periphery because plastic is, for example, bonded against plastic, in particular rubber against rubber and not, for example, rubber against a solid base plate material of possible bad adhesive compatibility.
3. Greater flexibility of the entire construction and thus smaller risk of damage and easier mountability in the aircraft.
4. All resultants of pressure loads in the bellows are cancelled toward the outside. Deformations of the originally plane outer surfaces occur hereby. A completely elastic system adopts these deformations easier than a composite method of construction containing rigid elements, which during operation always requires the use of special clamping conditions which resist deformation and breakage.
5. The manufacture of the bellows may be conducted within the same branch. Rubber companies are as a rule not familiar with aircraft building techniques, for example, riveting.
6. Easier disassembly for repairs. No danger of destroying the base plates during drilling of rivets.
7. Easy manufacturability, during assembly of the premanufactured components an adjusting error is not possible.
8. All in all, approximately 40% less expensive compared with conventional constructions.
The hinges are advantageously arranged on the wall of the air bellows, which is attached to the fuselage structure and does not suffer any deformations. Otherwise, difficulties with respect to a sufficient flexibility of the air bellows and wear problems could be generated during operation.